While on a call, you can access common in-call options by tapping icons at the bottom of the screen. (The first icon—variously labeled Add Call, Merge, or Swap—was discussed in previous sections.) Additional options are available via hardware controls and the Notifications panel.
During any call, you can tap the following icons:
• Extra Volume. You can boost in-call volume above the normal maximum by tapping the Extra Volume icon. When enabled, the icon is green. Tap it a second time to disable the volume boost.
• Noise Reduction. When activated, the noise reduction feature can improve call quality by reducing ambient noise. To toggle the state of this feature, press the Menu key and tap Noise Reduction On (or Off). ...